Personally couldn't care less if I get it 3 days earlier because already waited this long and I work from home atm (so the weekend doesn't really matter), but
-mass steam notifications on a Friday night with people logging in 7DTD would also be great for promotion, better than on a Monday at least.
-attracting fans of streamers who don't own the game can also happen while the rest are playing it.
-attracting streamers themselves can happen in many other ways like giving away some keys.
-those who are fans of streaming and those who don't watch streams are more likely to do what they always did, no matter what happened.
Perhaps the timing isn't ideal. As for streaming:
-yes it requires work and most importantly requires some points in charisma to be popular. Does it require as much work as the average job? It does not, but jobs, like people, aren't inherently equal. Just look at the Kardashians.
-are steamers asshats? Approx, as much as any other random group of people, which means most probably are
-is streaming a real form of entertainment? Yes, therefore the need for a crusade (I don't even watch football/soccer).